Methods and Results— Arterial injury was induced in wild-type (wt), leptin-deficient (lepob/ob), and leptin receptor–deficient (leprdb/db) mice. Compared with wt mice, lepob/ob and leprdb/db mice were protected from the development of neointima. Bone marrow transplantation experiments between wt and leprdb/db mice indicated that the vascular protection in leprdb/db mice was not attributable to lack of leptin receptor expression on bone marrow–derived elements. To investigate the role of the lepr-mediated signal transducer and activator of transcription 3 (STAT3) signaling pathway in the response to vascular injury, leprs/s mice homozygous for a leptin receptor defective in STAT3 signaling underwent femoral arterial injury. Despite similar obesity and blood pressure levels, the neointimal area in leprs/s mice was significantly increased compared with leprdb/db mice.

Conclusions— The molecular mechanism by which the leptin receptor mediates neointima formation and vascular smooth muscle cell proliferation is largely independent of the STAT3-dependent signaling pathways involved in energy balance.